Process of manufacturing cyanogen compounds



H. FOERSTERLING, H. PHILIP? AND R. N. SARGENT.

i PROCESS 0F MANUFACTURING CYANOGEN COMPOUNDS. APPLlcAloN FILED ocT. 29. 1913. RENEWED JAN. 14,1918.

1,332,439. Patented Mar. 2, 1920.

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HANS ,FOERSTERLINQ HERBEBT-PHILIER AND RALPH NELSON SARG-ENT, OF PERTE BOY, NEW JERSEY, ASSIGNORS T0 THE ROESSLER & HASSL'ACHER CHEMICAL G0., OF NEW YORK, N. YWA CORPORATION OF NEW YORK.

PROCESS OF MANUFACTURING CYANOGEN COMPOUNDS.

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Specification of Letters Patent.

Patented Mar. 2, 1920.

nApplication filed @ctober 29, 1913, Seria]-` No. 798,042. Renewed January 14, 1918. Seria1-No. 211,899.

To allen/tom t may concern:

Be it known that we, HANS Fonusrnnmnc, a citizen of the Empire of Germany, and HERBERT PHILIrr and RALPH NnLsoN SAR- cnNT, both citizens of the United States, all

, residing in Perth mboy, in the co-unty of @ur lnvention relates to the manufacture of cyanogen compounds and it particularly refers to their vmanufacture by syntheses from the 'respective constituent elements.

ln an application for Letters Patent Serial No. 739,352 by one of us, which has become Patent No. 1,288,716, issued Nov. 5, 1918, there is disclosed that the manufacture of metals or metal nitrid simultaneously with the production of luy-products in the form of cyanogen compounds may be achieved by decomposing suitable chemical compounds by volatile metals, preferably in a vaporous state, in the presence of carbonaceous and nitrogenous matter, the latter entering into combination with one or more of the constituents of the reaction.'

ln the aforesaid application there is also shown that the reaction liberates a large number of heat units so that the formation of the nitroge'nous compounds continues without further expenditure of fuel when once started.

Prior to the researches disclosed in the application referred to above we have discovered that the problem of manufacturing cyanogen compounds from their single constituents on a large scale involves carrying out a heat liberating process and that there are certain conditions which governthis process in regard to its liberatin heat so as to make it a convenient and e ective way of manufacturing said compounds.

Our process represents substantially a process for the fixation of nitrogen, by passing said gas under certain conditions, the details of which will be further pointed out below, into an incandescent mixture of carbonaceous material and an alkali or alkaline earth metal. One of the essential points to be observed in order to have the process go on as a heat-liberating or exothermic process is the temperature which is maintained during the process.

We have foundthat if carbon is heated to a temperature approximate to the boiling point of the metal the cyanogen compound of which is desired to be made, and for instance an alkali metal in a molten condition, for instance sodium metal, is introduced through a pipe into same, in the presence of nitrogen gas, the sodium metal readily volatilizes owing to the high temperature and the three elements combine to form sodium cyanid and liberate the heat of reaction in a Way which renders it available for the purposes of the process. appreciable combination is already evident at 700 C. and the absorption of nitrogen increases with the rise of temperature, the absorption labove 840 C. being very rapid, and extremely rapid between 1000o and 1100o C. rThe reaction between these elements is then under those conditions, as lalready pointed out above, of exorthermic nature and after the reaction has started in it is self-sustained by the reaction heat and no 'external heat need further be applied. rlhe point,'when the supply of external heat 'may be dispensed with, is of course inuenced by various matters, as for instance by the speed with which the materials are fed and consequently by the quantities of raw materials applied during a given time, by the surface of the carbon for radiatin heat, etc., so that this point can hardly be xed once and for all to hold good for any and all conditions. We may say, howeverthat we did not find it safe to shut off the supply of external heat until the boiling point of the metal applied is reached approximately, said boiling point'being of course subject to the respective changes in case pressure or partial vacuum is resorted to in the operation of the process.

Carbon is preferably a plied in its form of charcoal or other carlbonaceous matter, segregating carbon under the conditions prevailing in the process; charcoal, if applied for instance,-is provided in sufficient excess to absorb most of the cyanid of sodium formed and only a relatively small amount of same drains out in the molten form.

llt is but natural that the charcoal, after having absorbed so much sodium cyanid as cient there and as the charcoal there gradually becomes saturated the zone of reaction,

lit not checked, travels upward through the mass `without the addition of external heat,

inasmuch as the heat liberated by the process renders same self-sustaining by keepmg the charcoal incandescent.

The accompanying drawing, which represents a vertical sectional view of a suitable rractionvessel, surrounded by the usual furnace walls, illustrates one way by which our process may be practised.

The following example will serve for the elucidation of our process and method of operating the same: A suitable iron vessel A of strong construction to satisltactorily stand the wear and tear oi the process and not be affected by the products ot' the reaction, is provided at the lbottom with gat/evalves B and B to serve as outlet for the cyanid generated in the process. 'lhe charcoal C is lled into the vessel through a suitable opening D and rests on gatevalve B. The vessel Vis then heated externally until the boiling point of sodium is approximately reached, when sodium metal, preferably 1n molten form, though it may just as well be admitted in the form of vapor, is introduced by means of a pipe E, while nitrogen gas enters through pipe lE. As ,soon as the reaction is started, as indicatedby a reasonable rise in temperature, passing 800 G., the external heat may 'be shut od and the temperature rises, all other circumstances remaining unchanged, up t0 about 960 C,

Gases unreacted upon escape through pipe G.

llt is obvious in or the temperature prevailing in A that the sodium in whatever physical condition it is admitted into is readily transformed into a vapor penetrating the charcoal simultaneously with the nitrogen gas; as it is essential or the success of the process thatsodium be in vaporcus ormto enter into the reaction, therefore it is easily seen lthat sodium vapor proper can just as well be passed directly into the mass or that it, and the nitrogen likewise, may be admitted from below. As soon as the reaction starts the temperature of the mass rises according to the quantities used, thus the reaction zone is trying to gradually work its way up through the mass of charcoal, but in the operation of the process suitable provisions should be made to arrest the zone of reaction in its original location. 'lhe column of charcoal can be agitated by any suitable means as thereby the absorption of the sodium cyanid by the charcoal is more even and complete. In one case we introduced 784 kilos of sodium and a slight excess of an equivalent of nitrogen gas; we obtained 96.7 kilos NaCN which had drained from the charcoal, while the balance of about 157 0 kilos was retained in the charcoal mass, the latter showing an average test of about 64% NaC'N,

A slight excess of' nitrogen was merely supplied to keep any air from entering at the top of the vessel and is unnecessary with a closed top, in which case gases unreacted upon may leave the apparatus for instance through the charcoal inlet.

We have tonndfurther that the formation of cyanid vgoes extremely rapidly, which makes'the process very economical, and the apparatus for the production or large quantities represents a comparatively small unit. This process can ci course be worked either intermittently or continuously, in the latter case provision must be mamie for drawing od' of the mass from the bottom and for introducing fresh charcoal at the top.

' lt is obvious that the process described above may be carried out in any suitable apparatus which Awill readily allow the various operations described to be performed.'

As our invention demands that the metal. the cyanogen compound of which is desired, enters the reaction in the form of vapor, it is obvious that our invention relates rimarily. to the production of both alkali and alkaline earth cyanide, as the metals of these groups may be more or less easily vaporized; but the production of cyanids of such other metal, forming cyanids and being susceptible to volatilizatiom/ is also claimed as coming within the scope of our invention.

Many changes may also be made in the mode of operating vthe process ,as tar as its purely chemical side is concerned, which changes in their character will in no way deviate from the spirit of our. invention and we therefore shall not restrict ourselves to the mode of carrying out the process as described urther than the scope or' the appended claims demanmlsn Furthermore it is ci course understood that the heatin from outside may be effected lilo by the energyh of the reaction forming the lll@ pound by admitting a metal susceptible to volatilization and nitrogen gas to charcoal in excess and heated from the outside to about the boiling point of said volatile metal, discontinuing the supply ot outsideheat upon a. reasonable increase in temperature indicating start of reaction, generating heat by theL reaction between the elements,

promoting the combination of such elements,v

lvolatilization and nitrogen gas to charcoal in excess and heated from the outside to about the boiling point of said volatile metal, discontinuing the supply of outside heat upon a reasonable increase in temperature indicating the start of reaction, generating heat by the reaction between the elements,

promoting the combination of such elements.I

Jfurther admitted, by means of the heat of reaction, absorbing the generated cyanogen compound by the excess of charcoal present and producing thereby a mixture of charcoal and cyanogen compound to carry about 60% and more of the latter.

3. rEhe exothermic process of making cyanogen compounds, consisting in combining the elements of the desired cyanpgen compound by admitting a metal susceptible to volatilization and nitrogen gas to charcoal in excess and heated from the outside to about the boiling point of saidvolatile metal, starting the reaction at the bottom or the reaction mass, generating heat by the reaction between the elements, absorbing the generated cyanogen compound in the charcoal and arresting the reaction zone in its original location.

4. rlhe exothermic process of making cyanogen compounds, consisting in combining the elements of the desired cyanogen compound by admitting a metal susceptible to volatilization and nitrogen gasto charboal in excess and heated from the outside to about the lboiling point of said volatile metal, starting the reaction at the bottom of' ther reaction mass, discontinuing the supply of outside heat upon a reasonable increase in temperature indicating the start of reaction, generating heat by the reaction between the elements, promoting by means of the heat of reaction the combination of such elements further admitted, absorbing the` alkali cyanid, consisting in combining the elements of the desired alkali cyanid by admitting the respective alkali metal and nitrogen gas to charcoal in excess and heated from the outside to about the boiling point of said alkali metal, discontinuing the supply of outside heat lupon a reasonableI increase in temperature indicating start of reaction, generating heat by the reaction between the elements, promoting the combination of such elements, further admitted, by meansof the heat of reaction and absorbing the greater part of the generated cyanid by the excess of charcoal present.

6. ,The exothermic processl of making an alkali cyanid, consisting in combining the element-s of the desired alkali cyanid by admitting the (respective alkali metal and nitrogen. gas to charcoal in excess and heated from the outside to about the boiling point o-said alkali metal, discontinuing the supply of outside heat upon a reasonable increase in temperature indicating start of reaction, generating heat by the reaction between the elements, promoting the combination of such elements, further admitted, by means of the heat of reaction, absorbing the generated cyanid by the excess of charcoal present and producing thereby a mixthe respective alkali metal and nitrogen gas to charcoal in excess and heated to about the boiling point 01'. said alkali metal, starting the reaction at the bottom of the reaction mass, generating heat by the reaction between the elements, absorbing the generated cyanid in the charcoal and arresting the reaction zone in its original location.

8. rlhe exothermic process of making sodium cyanid consisting in combining sodium, carbon and nitrogen gas, by admitting sodium and -nitrogen gas to charcoal in excess and heated from the outside to about the boiling point of sodium, discontinuing the supply of outside heat upon indication of started reaction upon reasonable increase in temperature, generating heat by the reaction between the above elements, promoting the combination of the respective elements, further admitted, by means of the heat of reaction and absorbing the greater part of the generated sodium cyanid by the excess ot charcoal present.

9. yThe exothermic process of making sodium cyanid consisting in combinin sodium, carbon and nitrogen gas by admitting sodium and nitrogen gas to charcoal in excess and heated from the outside to about the boiling point of sodium, discontinuing the supply of outside heat'upon indicationof started reaction upon reasonable lncrease :action between the above elements, promotintemperature, generating heat by the reing the combination of the respective elements,` further admitted, by means of the heat-of reaction, absorbing the generated sodium cyanid by the excess of charcoal present and producing thereby a mixture of charcoal and sodium cyanid to carry about 60% and more of the latter.

10. The exothermic process of making sovdium cyanid, consisting in combining sodium, carbon and nitrogen gas by admitting a sodium and nitrogen gas to charcoal in eX- cess and heated from the outside to about the boiling point of sodium, starting the reaction at tbe bottom of the reaction mass,

` generating heat by the reaction between tlrf'el above elements, absorbing the generated sodium cyanid in the charcoal and arresting the reaction zone in its original location.

11. The exothermic process of making sodium cyanid, consisting in combining sodium, carbon and nitrogen gas by admitting sodium and nitrogen gas to charcoal in excess and heated from the outside to about the boiling point of sodium, starting the reaction at the bottom of the reaction mass,-

both containin and more of the cyan-4 i,

ogen compoun and arresting the reaction zone 1n 1ts origlnal location.

HANS FUERSTERLNG. HERBERT PHHPP. RALPH NELSUN SARGENT.

Witnesses:

MARIE Nr/rnL, @mo K. ZWINGENBERGER. 

